As is well known, a conventional optical receptacle is constructed as disclosed in Patent Document 1, for example, by: inserting a cylindrical embedded ferrule into a base end portion of an inner hole of a sleeve through press-fitting or bonding; and fitting a sleeve holder around an outer periphery of a base end portion of the sleeve. Then, a ferrule (plug ferrule) is inserted into a tip side of the inner hole of the sleeve, and an optical fiber on the plug ferrule side and an optical fiber on the embedded ferrule side are brought into contact with each other at respective end faces for optical connection.
Another known conventional optical receptacle, which is different from the optical receptacle described above, is constructed as disclosed in Patent Document 2, for example, by: inserting a rod formed of an optical material such as glass into a base end portion of an inner hole formed in a main body of a semiconductor module; and bringing into contact with each other a tip face of the rod, and an end face of the ferrule inserted into a tip side of the inner hole. The tip face (B face in Patent Document 2) of the rod brought into contact with the end face of the ferrule is subjected to spherical polishing. This rod may be regarded as being inserted into the inner hole of the module main body through press-fitting or bonding in consideration of the fact that the tip face of the rod is subjected to spherical polishing and an operation of fixing the rod must be performed while the tip face subjected to spherical polishing is protected.    Patent Document 1: JP-A-10-332988 (FIG. 4)    Patent Document 2: JP-A-04-223412